1. Field of the Invention
The present invention relates to a ventilation device for use with a fuel tank mounted on a motor vehicle.
2. Description of the Prior Art
Fuel tanks mounted on motor vehicles have an air vent pipe attached to a top wall thereof for discharging air upon a pressure buildup in the tank due to an increase in the air temperature. To prevent fuel from leaking through the air vent pipe when the fuel tank is tilted while allowing air to vent off, there has been proposed a fuel tank ventilator in Japanese Laid-Open Patent Publication No. 51-77716 based on West German Patent Application No. P 24 56 726.8.
The aforesaid proposed ventilation device comprises a box extending transversely of the motor vehicle and depending downwardly from a top wall of the fuel tank, the box communicating with an air vent pipe. The box includes transverse side walls joined respectively to elongated inner ventilation pipes extending along the lower surface of the box and projecting laterally with their distal ends directed in opposite directions. Although the proposed ventilation device is well capable of air ventilation and preventing fuel leakage, it requires supports for supporting the two elongated inner ventilation pipes in lateral directions within the fuel tank. The number of parts employed is therefore increased, and the procedure for connecting the parts is complex to perform.